Friction Force Calculator Formula
Understand the math behind the friction force calculator. Each variable explained with a worked example.
Formulas Used
Friction Force
friction = mu * normal_forceVariables
| Variable | Description | Default |
|---|---|---|
mu | Coefficient of Friction | 0.5 |
normal_force | Normal Force(N) | 100 |
How It Works
Friction Force
Friction opposes relative motion between two surfaces in contact.
Formula
f = mu * N
where mu is the coefficient of friction (static or kinetic) and N is the normal force perpendicular to the surface.
Worked Example
A 10 kg box on a flat floor has a kinetic friction coefficient of 0.5.
- 01Normal force N = m * g = 10 * 9.81 = 98.1 N
- 02f = mu * N
- 03f = 0.5 * 98.1
- 04f = 49.05 N
Frequently Asked Questions
What is the difference between static and kinetic friction?
Static friction prevents an object from starting to move and is generally larger. Kinetic friction acts on an already moving object and is usually smaller.
Can the coefficient of friction exceed 1?
Yes. Some rubber-on-rubber contacts have coefficients above 1. The coefficient is not bounded by 1.
Does friction depend on contact area?
For idealized surfaces, friction is independent of contact area. In practice, very soft or deformable materials may show some area dependence.
Learn More
Guide
Understanding Newton's Laws of Motion
A comprehensive guide to Newton's three laws of motion. Learn about inertia, force and acceleration, action-reaction pairs, and how these principles govern everyday physics.
Ready to run the numbers?
Open Friction Force Calculator